Childhood cancer is the number one cause of death by disease in children, and parents of children with cancer are at significant risk for symptoms of anxiety, distress, depression, and posttraumatic stress. Access to social support buffers psychological adjustment for parents of children diagnosed with pediatric cancer, and parents who have lower perceived social support are more likely to experience uncertainty, anxiety, depression, and post traumatic stress symptoms. A problem, however, is that previous studies typically rely on global measures of parents' perceptions of access to support, leaving important questions regarding the precise characteristics of support networks that improve parental psychological outcomes unanswered. In this R01 program of research by a new and early stage investigator we will use both prospective longitudinal social network data and Ecological Momentary Assessment (EMA) to capture daily network experiences surrounding stressful treatment events to examine how network characteristics at multiple levels (ego, alter, ties) shape access to supportive resources and parental psychological outcomes. In Aim 1 we will collect prospective longitudinal network data to examine how parents' social network characteristics evolve (e.g. size, composition, online/offline) over time, and how the relationship between network characteristics and access to specific kinds of supportive resources (e.g. informational, emotional, tangible) changes over time. We will also examine the association between access to specific kinds of support and parental stress, anxiety, positive affect and negative affect over time. In Aim 2 we will use daily EMA data to explicate the dynamics of network activation during especially stressful treatment experiences, and the relationship between network activation and parents' anxiety, stress, positive affect, and negative affect. Findings will make significant conceptual advances through (1) clarifying the network properties that are associated with access to different kinds of support and (2) characterizing the patterns of network engagement that are associated with improved parental psychological adaptation to pediatric cancer. Our methodologically innovative design combines both prospective longitudinal network data and EMA to capture daily network experiences surrounding stressful treatment events, and will enable examination of between-person and within-person associations among social network characteristics and parental anxiety, stress, positive affect and negative affect. By refining understanding of the network characteristics associated with improved parental psychological outcomes, findings from the proposed program of research will have high translational significance by identifying profiles of network characteristics that are associated with parental anxiety, stress, negative affect, and positive affect. These findings will provide the evidence base to refine clinical interventions to improve psychological adjustment to cancer caregiving. Our findings will also inform supportive care programs by identifying which kinds of support services are most needed for parents that are not able to access particular types of support through personal networks.